By Theresa Tedesco and Matt Hartley (Writers, Financial Post)
Under intense pressure from a group of shareholders, Research in Motion Ltd. is preparing to unveil a corporate shakeup at the beleaguered BlackBerry maker that could see co-founders Mike Lazaridis and Jim Balsillie relinquish their titles as co-chairmen of the board, according to sources.

Barbara Stymiest, an independent director who joined RIM’s board in 2007, is believed to be the leading candidate to replace Messrs. Balsillie and Lazaridis as chair, sources familiar with events said.

A committee of seven independent directors of RIM’s board, including Ms. Stymiest, have been examining the company’s board structure, including the merits of having an independent chair rather than a lead director and the “business necessity” for Messrs. Lazaridis and Balsillie — who are also co-CEOs — to hold significant board titles.